Fix the static_assert added in r279536.

The assertion doesn't always hold true as sizeof(SDNodeBits) isn't equal
to sizeof(uint16_t) for some targets. For example, sizeof(SDNodeBits)
evaluates to 1, not 2, for ARM's APCS targets.

llvm-svn: 279797

llvm/include/llvm/CodeGen/SelectionDAGNodes.h

@@ -1098,8 +1098,8 @@ public:
   unsigned getRawSubclassData() const {
     uint16_t Data;
     memcpy(&Data, &SDNodeBits, sizeof(SDNodeBits));
-    static_assert(sizeof(SDNodeBits) == sizeof(uint16_t),
-                  "SDNodeBits field too small?");
+    static_assert(sizeof(SDNodeBits) <= sizeof(uint16_t),
+                  "SDNodeBits field too large?");
     return Data;
   }